Objective of this synthesis report is to summarize the main achievements of the WELLMA-2 project. Based on the preparatory phase WELLMA-1 (2007-2009), the main project phase WELLMA-2 (2009-2012) included extensive laboratory, pilot-scale and field site investigations aiming at optimizing the operation and maintenance of drinking water production wells with respect to costs, energy efficiency and sustainability. The main reason for inefficient well performance is so-called well ageing. Deposit formation due to multiply correlated biological, chemical and/ or physical clogging processes in and around the well cause a decrease in performance. Thus, the interdisciplinary WELLMA-project team aimed at improving the efficiency of drinking water production wells by providing a scientific basis to support operators in their efforts to reduce well ageing. This included the development of guidance and recommendations for an adapted and well-planned operation scheme and maintenance strategy to sustain or reinstall the well performance. Well ageing processes were intensively studied at a multitude of vertical drinking water production wells located in Berlin, Germany and near Bordeaux, France. Thereby, classical monitoring and diagnosis methods, such as pumping tests and TV inspections, but also newly developed own experimental setups, such as the in-situ measurement of oxygen, depth-oriented water sampling or the exposure of object slides and bio-reactors for biofilm growth were applied. This synthesis report follows the project outline featuring four work packages dealing with (i) the identification of ageing types and the site-specific ageing potential from optimal data processing of site and well characteristics to provide decision support for the diagnosis and subsequent optimisation of well operation, monitoring and maintenance, (ii) field methods and experimental setups applied within the WELLMA-project to investigate mixing processes, oxygen uptake and biofilm formation, (iii) the impacts of intermittent operation on the uptake potential and distribution patterns of oxygen, and (iv) the efficiency of hydrogen peroxide treatments for preventive well maintenance against biochemically induced iron ochre formation and the oxygen uptake potential correlated to the decomposition of H2O2. Intermediate data were presented at various occasions at scientific and practiceoriented conferences, e.g. the Association for General and Applied Microbiology (VAAM), the International Water Association (IWA) Groundwater conference, International Association of Hydrogeologists (IAH), Berlin-Brandenburger Brunnentage, Wasser Berlin etc. and in related papers. A publication list is given at the end of this synthesis report.

Combined sewer overflows (CSO) after heavy rainfall can cause acute depletions of dissolved oxygen (DO) in the Berlin River Spree. Further aggravation of ecological deficits can be expected from global climate change. A planning instrument for CSO impact assessment under different sewer management and climate conditions has been developed at Kompetenzzentrum Wasser Berlin. It couples the sewer model InfoWorks CS, the river water quality model Hydrax/QSim and an impact assessment tool. The planning instrument was validated for the years 2010 and 2011. Simulation results for the critical parameters discharge and DO concentrations in the Berlin River Spree agree well with measurements. Although not all observed DO deficits can be simulated accurately, the very good representation of processes related to the oxygen budget allows assessing relative changes in boundary conditions, e.g. from climate change or different CSO control strategies. The conducted scenario analysis indicates that the coupled sewer-rivermodel reacts sensitively to changes in boundary conditions (temperature, rainfall, storage volume and other CSO control strategies, etc.). Based on the simulation year 2007 – representing an extreme year with regards to CSO volume and critical conditions in the river – sewer rehabilitation measures planned to be implemented until 2020 are predicted to reduce total CSO volumes by 17% and discharged pollutant loads by 21 - 31%. The frequency of critical DO conditions for the most sensitive local fish species will decrease by one third. For a further improvement of water quality after the year 2020, the reduction of impervious surfaces emerges as a very effective management strategy where feasible. A reduction of the impervious connected area by 20% results in a decrease in the frequency of critical DO conditions by another third. The studied increase in surface air and water temperature as part of the climate change scenarios leads to a significant aggravation of DO stress due to background pollution in the Berlin River Spree, while acute DO depletions after CSO are barely affected. However, changes in rain intensity have a considerable effect on CSO volumes, pollutant loads and the frequency of critical DO concentrations. A general reduction of discharged pollutant loads by 60% based on the sewer status 2020 can prevent critical DO conditions in the Berlin River Spree, even for the exceptionally rain intense year 2007. A detailed analysis of river processes after CSO, has shown that the biodegradation of organic carbon compounds is the most important contributor to acute DO depletions in the Berlin River Spree. An additional impairment of DO conditions is caused by the inflow of oxygen free CSO spill water and suspended solids into the Berlin River Spree. In this report, CSO impacts under different management strategies or climate change conditions are assessed only for a part of the Berlin combined sewer system (although the main part) and for one exemplary year. An extension of the planning instrument to the entire combined sewer system would enable to evaluate the full impact of measures. For a robust prediction of future CSO impacts it is also recommended to test different simulation periods or conduct long-term simulations.

Recent infrastructure studies underline the general deterioration of sewer system and the risk reversing public health, environment and increasing costs (ASCE, 2009). Since the origin of sewer systems in the 19th century, sewers have been installed at different periods using available standards and technologies. Sewer assets have limited service life and it is crucial to assess their condition throughout their life cycles to avoid potential catastrophic failure and expensive emergency rehabilitation due to their deterioration (Hao et al., 2011). This report first presents the wide panel of inspection technologies available to obtain information about sewer defects and condition. Visual inspection (e.g. Closed-circuit television CCTV, zoom camera) appears to be the industry standard for sewer inspection. It provides visual data (images and/or videos) of the internal surface of the pipe. Defects are usually coded manually by the inspection staff according to standard coding methods. In Europe, the current codification system is the normative EN 13508-2 for visual inspection (EN 13508-2, 2011) used by the CEN-Members (European Committee for Standardization). In addition, physical techniques are available that can give further information and details about pipe defects. These techniques do not replace the CCTV inspection but can give deeper insights on the type and severity of defects. Sonar and Lasers enables to analyze pipe geometry and can identify defects such as deflections, cracks, sediments or corrosion. Ultrasonic testing and magnetic flux leakage (MFL) are applied directly on the pipe wall. They enable to measure wall thickness and detect pipe defects such as corrosion, deflections and cracks. Ground Penetrating Radar (GPR) and Infrared Thermography are used from above ground and are useful to locate pipes and identify bedding conditions, voids and leaks. Finally, network wide inspection technologies like smoke testing or Distributed Temperature Sensing (DTS) can locate cross-connections and/or sewer infiltration. The purpose, inspection procedure and limitations of these methodologies are briefly presented. On a second step, this report presents the available classification methodologies developed to interpret automatically visual CCTV inspection reports and evaluate sewer condition. These methodologies enable to transfer the extensive amount of visual inspection data from CCTV inspection into a more easily manageable number, useful to support asset management practices. Most approaches have a similar goal: they aim to rank rehabilitation priorities and support municipalities in the definition of rehabilitation programs. They do not pretend to replace the knowledge and analysis skills of a local expert but can help him to identify rehabilitation priorities. All methodologies provide an overall condition score for each sewer segment or sub-scores for different requirements (e.g. structural and operational condition) or dysfunctions. From the review of available methodologies, two main approaches can be distinguished: priority based and substance based methodologies. For priority based methodologies, the calculation of sewer condition grades is based on the most severe defects, the density of defects and/or the defects length. Condition grades express the priority of rehabilitation, i.e. the emergency of action regarding the probability of failure or collapse. For substance based methodologies, the final score is calculated based on the length of sewer that will be affected by rehabilitation actions. Substance based methodologies do not aim to assess the condition of sewers but rather to rank sewer pipes considering the amount and type of rehabilitation needs: replacement, renovation and repair. Each methodology aggregates and combines sewer defects in a very different way making very hazardous the benchmarking of final scores from different methods. Therefore, municipalities using different evaluation system are not able to benchmark the condition of theirs networks. Finally, the accuracy of the classification results remains a key issue, crucial for the further use of inspection data to support asset management strategies.

This report aims at documenting the scientific evidence at 4 managed aquifer recharge (MAR) sites in India after 18 months duration of the EU (European Union) funded project SAPH PANI. The site investigations include compilation of previously existing data, a wide range of field experiments, surface-/groundwater and sediment sampling, data analysis, interpretation and the development of (preliminary) conceptual models. The MAR sites are realised under a wide range of geological and hydrological conditions and the covered aspects can be summarised as:...

Water is one of the sectors where climate change will be most pronounced. While the extents of the impacts are not known yet, it is the right period to prepare the utilities to adapt to the global changes in an urbanising world. Adaptation to climate change, though not always perceived as such, is often already reality in the urban water sector. Several adaptation strategies have been tested to address the key questions: Adapt to what? What to adapt? How to adapt? In this context, within the framework of the EU-project PREPARED, a tentative classification and catalogue of implemented initiatives in the water sector has been compiled. This catalogue is organised into four major categories of initiatives: (1) risk assessment and management, (2) supply-side measures, (3) demand-side measures and (4) global planning tools. The document aims at providing examples on how utilities could go ahead into preparing their water supply and sanitation systems to climate change. Initiatives include various measures ranging from the promotion of active learning to the prevention of sewer flooding and water conservation measures. Within PREPARED, this catalogue is supporting the development of solutions. Being a living document, it is updated regularly along the project when new solutions and initiatives are known. In addition, this work and the subsequent database of adaptation initiatives are accessible to a broader audience thanks to the web-based ‘WaterWiki’ of the International Water Association (IWA).

Risk-based management approaches are more and more used in the water sector and are promoted by the WHO. As a first step towards an overall risk-based management approach of the agricultural wastewater reuse concept of Braunschweig this report conducts quantitative microbial risk assessment (QMRA) and quantitative chemical risk assessment (QCRA) of heavy metals. Scenarios for microbial risks are conducted for fieldworkers, nearby residents and children ingesting soil using a 1000 trial Monte Carlo Simulation. As a tolerable value of risk an additional disease burden of 1 µDALY is set following the current WHO guidelines. For heavy metals impacts on the terrestrial and aquatic ecosystems as well as on human health are assessed using the methods outlined in the European Union Technical Guidance Document on Risk Assessment (TGD). Concerning microbial risks risk-based targets are set in terms of additional required pathogen reduction in the STP Steinhof. Based on the model results an additional reduction of 1.5log units is derived for viruses, for which the highest annual risks of infection per person per year (pppy) is calculated in all scenarios. Concerning heavy metals the model indicates an increasing tendency of soil concentrations over time and identifies Cd as the only metal which is currently of concern. Risk reduction measures should be considered for this metal. Recommendations are given concerning necessary validation and additional monitoring for eliminating uncertainties within the model.

The goal of this study is to demonstrate the application of Life Cycle Assessment as a tool for systems analysis in wastewater treatment. Therefore, the process for sludge treatment and disposal at the WWTP Berlin-Waßmannsdorf has been analysed with the methodology of Life Cycle Assessment (LCA) to determine the total cumulative energy demand and the carbon footprint of the system as exemplary indicators. In addition to the characterization of the status quo in 2009, several measures for an energetic optimization of the system have been evaluated in their effects on the energy balance and greenhouse gas emissions. The process model of the system encompasses all relevant processes of sludge treatment and disposal, including the supply of electricity and chemicals, transport and incineration of the sludge, and treatment of sludge liquor which is recycled back to the WWTP inlet. Products recovered during sludge treatment (biogas from anaerobic digestion and MAP fertilizer) and disposal in incineration (electricity or substitution of fossil fuels) are accounted by credits for the respective substituted products. Overall, sludge treatment and disposal in Berlin-Waßmannsdorf is an energy-positive process, recovering a net amount of primary energy of 162 MJ (45 kWh) per population equivalent and year (PECOD*a). This is mainly due to the biogas generated in anaerobic digestion and the substitution of fossil fuels in co-incineration. Similarly, the carbon footprint of the process reveals an amount of 11.6 kg CO2-eq/(PECOD*a) as avoided emissions, thus indicating the environmental benefits of energy recovery from sewage sludge. However, process emissions of the powerful greenhouse gases CH4 and N2O are estimated based on generic emission factors from literature, and can have a distinct influence on the overall carbon footprint. This underlines the necessity to support the results of this LCA with primary data from monitoring of emissions on-site. The evaluation of optimization measures shows the benefits of a system-wide analysis: an enhanced recovery of energy is partially offset by increased energy demand, and the carbon footprint does not always correlate with the energy balance. The different routes for sludge disposal differ heavily in their environmental profile and show potentials for optimisation, especially in mono-incineration of sewage sludge. Some measures are beneficial for both energy and carbon footprint (addition of co-substrates into the digestor, utilization of excess heat with an Organic Rankine Cycle process), while others can decrease energy demand but may potentially increase the carbon footprint (treatment of sludge liquor by deammonification, thermal hydrolysis of excess sludge). Overall, the method of Life Cycle Assessment proved to be well suited for a systematic analysis of the environmental footprint of the activities of Berliner Wasserbetriebe. In the future, the existing process model can be extended to include the entire wastewater treatment plant for a comprehensive evaluation of its environmental profile, e.g. for providing information on the environmental consequences of prospective concepts for site development.

As a part of well field optimization the pump, as a key component in water extraction systems and its energy saving potentials have to be checked. In addition to the project deliverable D2.1 “Literature review on theoretical pump and motor efficiency of submersible pump systems” the availability of innovative and energy saving submersible pumps on the market has to be verified. Therefore, the market has been scanned and evaluated. The purpose of this document is to present the results of the market analysis for efficient pumps and to assess realistic energy saving potentials that are achievable with today’s technology. This achievement can be reached by either selecting more efficient centrifugal pumps or motors (evaluated in this study), or by considering some boundary conditions such as losses in power supply cables, operating mode or the use of variable speed drives. These accompanying conditions were also discussed at the workshop and are presented as a short summary in the last chapter of this paper.